This study is intended to advance the field of adolescent alcohol treatment research. Use and abuse of alcohol and illicit drugs by adolescents is a major national problem. Pediatricians and other primary care medical providers are in a unique position to identify this use during routine office visits and offer appropriate treatment before serious harm results. The long-term objective of this investigative team is to develop and test a clinical protocol for substance abuse screening, assessment, intervention and referral by primary care physicians who treat adolescent patients. As the first step, this study will refine and validate an alcohol and drug screening test that - like the CAGE test for adults - is brief, verbally administered, simple to score, and has an easy-to- remember mnemonic. The investigators have previously demonstrated that the 6-question CRAFFT test has good sensitivity and specificity for identifying youth that require intensive substance abuse treatment. The specific aim of the present study is to shorten the CRAFFT, and validate the new test using two criterion standards: a risk assessment (the POSIT alcohol/drug scale) and a structured diagnostic interview yielding DSM-IV alcohol and drug-related diagnoses (the ADI). Subjects will be 14-18 year old patients arriving for routine medical care at an adolescent clinic. The relationship between the CRAFFT questions, the POSIT, and ADI-determined diagnoses will be determined. Logistic regression and factor analysis will be performed to determine the minimum number of items for the brief test. Sensitivity, specificity, and predictive values will be computed. Subjects that are POSIT-positive and ADI-negative will be considered to be in the DSM-PC Problem-Use category, a developmentally important phase of substance abuse progression. The psychometric abilities of the brief test for identifying this group will also be determined. Optimal cut-points will be derived from ROC curves. The investigators hypothesize that the brief test will be able to assist clinicians in discriminating patients appropriate for brief office interventions from those that need prompt referral to substance abuse specialists. This new test will be most valuable to medical clinicians that serve adolescent patients, and its dissemination will enhance early identification and referral-to-treatment of adolescent problem drinkers and drug users. The results of this study will ultimately lead to the development and testing of a physician's guide to helping adolescent patients with alcohol/drug problems.